Crusoe off track (6)
I believe the answer is:
course
'track' is the definition.
(I know that course is a more specific form of the action the track)
'crusoe off' is the wordplay.
'off' indicates an anagram.
'crusoe' anagrammed gives 'COURSE'.
(Other definitions for course that I've seen before include "Syllabus" , "soup?" , "Channel" , "Route along which something travels" , "Mode, of action say" .)